1. Field of the Invention
This invention relates to laminated glass articles comprising Infra Red reflective films imbedded in the interlayer. This invention more particularly relates to said glass laminates wherein the interlayer is an ethylene/unsaturated acid copolymer ionomer.
2. Description of the Prior Art
Films that either reflect or absorb infra red (IR) light, such as are described in U.S. Pat. No. 6,368,699, WO 9936808A1, WO 9936810A1 and U.S. Pat. No. 5,071,206, can be embedded in laminated glazing structures by sandwiching the film between two sheets of interlayer material, and finally between sheets of glass. Typically interlayers used for this purpose are polyvinyl butyral (PVB) polymer, and the IR film can be autoclaved between the PVB sheets so that the sandwich is sealed along the edges with the PVB.
However, commercially available PVB is typically plasticized and includes other components such as free acidic groups and various ions, all of which can render the structure prone to rapid and intense moisture absorption. Moisture absorbed into the PVB layers can facilitate and accelerate corrosion of the surfaces of coated imbedded IR film. Also, with certain multi-layered films incorporating an optical stack, the plasticizers used in PVB interlayers can bleed between the film layers at edges and cause enough separation to create highly colored iridescence called “edge brightening”. Edge brightening is not a desirable characteristic in glass laminates of this type.
It can be desirable to form an IR-blocking laminate film that will not readily absorb moisture or cause corrosion or edge brightening.